We could barely tell, of course -- the dress actually reminded us of a similar Marc Jacobs number worn recently by Nicole Richie and Miley Cyrus. But we always respect a celeb who reminds us that you don't need to spend a fortune to look red carpet-ready when a dress from Topshop, ASOS or H&M will do.

Check out Pixie's look. Will you be heading over to Topshop.com to buy it for yourself?